# Introduction

This document describes many of the `PyGObject` version 2.12 classes and their methods and associated functions. Deprecated classes, functions and methods have been specifically left out of this reference though classes that have become deprecated since PyGObject 2.0 have been left in but annotated with a deprecation warning. This document attempts to document as much of the `PyGObject` `API` as possible but there are undoubtedly errors and omissions. If you discover any of these please file a bug report at bugzilla.gnome.org for the `pygobject` project. Specific areas that have not been documented include:

- The GParamSpec class

This reference describes the API for `PyGObject` as of version 2.11.0+ and assumes that the additional API changes for version 2.12 will not be significant. There will undoubtedly be changes that are not reflected in this reference. The differences in the API between version 2.0 and previous versions are denoted in this reference with a Note that describes the availability of the object, constructor, method or function. Any of these that do not have a notation can be assumed to be available in all versions of PyGObject from 2.0 and up. The source code must be consulted if this reference and your version of `PyGObject` seem to differ. You are encouraged to use the latest version of `PyGObject` that is available. See the `PyGTK` homepage for more information and more resources on how to use PyGObject as well as help in its development.

The Reference contains a chapter for each `PyGObject` module containing the class descriptions. The class descriptions are arranged alphabetically within the chapters. Currently there is one module chapter:

The `gobject` module

  The classes that are included in the `gobject` module of `PyGObject` and are accessed similar to: gobject.GObject. These classes are the base object classes that the `gtk` and `gtk.gdk` module classes are built on.

## Reference Page Format

Each `PyGObject` class is described in a reference page that has a number of sections in a fixed format. Each reference page will have a subset of the following sections:

Name

  The name and a one-line description of the class.

Synopsis

  A synopsis of the class and its methods and optionally a list of associated functions.

Ancestry

  The list of the parent classes of the class. This section may not be present in all class descriptions.

Properties

  A list of the properties (internal state) supported by the class. This section may not be present in all classes. The property descriptions include the name, the access operations (e.g. Read, Write), and a brief description. Properties are accessed using the `gobject.set_property`() and `gobject.get_property`() methods that are available to every `PyGObject` object. This section may not be present in all class descriptions.

Attributes

  A set of internal object state data accessible as Python attributes (e.g. object.attr). The attribute descriptions include a name by which the attribute data is accessed, the access mode (e.g. Read, Write), and a brief description of the attribute. Most `PyGObject` classes do not support attributes so this section is not present in most class descriptions.

Signal Prototypes

  A list of the signals supported by the class including the signal name and a synopsis of the signal handler function prototype. This section may not be present in all class descriptions.

Description

  A description of the class and possibly some of the methods supported by the class.

Constructor

  The description of the class object constructor including the synopsis with brief parameter descriptions and a description of th use of the constructor. There may be more than one constructor description if the constructor supports different parameter lists. This section may not be present in all class descriptions.

Methods

  A list of methods supported by the class. Each method description includes: a synopsis of the method and its parameters as well as a brief description of each parameter and return value (if any); and, a description of the use of the method.

Functions

  A list of related functions. Each function description includes a synopsis of the function and its parameters and return value (if any), and a description of the use of the function.

Signals

  A list of signals including a synopsis of the signal handler prototype function with its parameters and return value (if any). The signal emission conditions are briefly described. This section is not present in all class descriptions; specifically, the `gtk.gdk` classes do not usually support signals.

The function and method synopsis parameters are displayed in bold to denote Python keyword parameters. Also if the parameter is optional its default value will be displayed. For example the `gobject.signal_lookup`() function synopsis is:

    	gobject.signal_lookup
    	name
    	type

The parameters `name` and `type` are keyword parameters that can be specified in a call either by position or keyword (in which case position is not important). The following calls have the same result:

      id = gobject.signal_lookup("clicked", gtk.Button)
      id = gobject.signal_lookup("clicked", type=gtk.Button)
      id = gobject.signal_lookup(name="clicked", type=gtk.Button)
      id = gobject.signal_lookup(type=gtk.Button, name="clicked")

Parameters that are not keyword parameters are displayed in italic and must be specified positionally but may also be optional.